IR 05000186/1998201
| ML20199J849 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Columbia |
| Issue date: | 02/02/1998 |
| From: | Weiss S NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20199J785 | List: |
| References | |
| 50-186-98-201, NUDOCS 9802060050 | |
| Download: ML20199J849 (14) | |
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Enclosure 2 U.S. NUCLEAR REGULATORY COMMISSION Docket No: 50-186 License No: R 103 Report No: 50 186/98201 Licensee: University of Missouri at Columbia Facility Name: University of Missouri at Columbia Research Reactor Location: Columbia, Missouri Dates: January 12 15,1998 Inspectors: T. M. Burdick Approved by: Seymour H. Weiss, Director Non-Power Reactor and Decommissioning Project Directcrate .
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Executive Summary University of Missouri at Columbia Research Reactor (MURR)
Report No. 50-186/98201 (DRPM)
This routine, announced Mspection included aspects of organization, operat.ons and maintenance activities (39745) review, audit, and design change functions (40745) reacto-operator requalification and medicals (69003); procedures (42745); fuel movement (60745);
surveillance (61745) experiments (69005): emergency preparedness (32745); and event follow-up (92700).
OraanizatlE The licensee met the requirements for staffing the reacto Ooerator Recualificallen One violation of the licensee's program was identified by the inspecto Ooerations. Maintenance. Review. Audit. and Deslan Chance. Procedures. Fuel Handlin Exoeriments. and Emeroency Preoaredness The inspected activities were conducted in accordance with license requirement Survcillance The licensee identified, immediately corrected, and promptly reported a violation of a Technical Specifications (TS) requirement for reactor protection channel operability, that met the NRC Enforcement Policy criteria to be non-cite Event Follow Uo The reactor underwent an unexplained positive reactivity addition followed by a high power reactor scram on December 9,1997. The licensee took acceptable action to report the event and examined possible causes before retuming the reactor to operation. No TS limits were cxceede _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ - _ _ - - _ _ _ _ - _ - _
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DETAILS Summarv of Plant Status The MURR reactor facility has been operating the pasi year without interruption other than for planned maintenance and refueling periods. The new Director has been at the facility since early December '997. The reactor experienced one unexplained positive reactivity addition terminated by i high power reactor scram which is discussed in Section 9.0 of this repor .0 Organization, Operations and Maintensnce Insoection Scone (39745)
The inspector reviewed the f acility organization and operations and maintenance activities to verify that they were maintained as required by the T Observations and Findinas Dr. Edward A. Deutsch became the n3w Dl7ctor for the f acility in Decembe Operational staffing has been stable with little turnover. All but one member cf the shif t staffing had a senior reactor operator's licent The inspector reviewed operations and maintenhnce logs and records. The Beryllium reflector replacement was a major task that was completed without i inciden During a reactor startup the inspector observed operators, engineers, and technicians troubleshoot a micro switch associated with rod control. Their techniques were methodical and safety oriente One unscheduled shutdown due to an unexplained positive reactivity addition was reviewed by the inspector and discussed in the Event Follow Up Section 9.0, Conclusions The licensee met the requirements for staffing and operating and maintaining the reacto .0 Review and Audit, and Design Change Insoection Scone (40745)
The inspector reviewed the f acility review and audit, and design change activities to verify they were' consistent with the technical specification l
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2 Qhservations and Findinos Committees responsible for reviewing licensee activities were scheduled and attended by a quorum as required. The topics and activities were reviewed in accordance with the technical specification '
The licensee obtained committee approval to install a new power range channel, which would be assigned the high power reactor trip function currently assigned to the Wide Range Monitor, channel 4. This may solve e problem with frequent spurious trips caused by channel 4 which will b3 retained for regulating rod control and indication only. Installation was being delayed until the arrival of a new recorde The licensee complated design, review, and installation of a new rod position indication system. The system appeared to work properly, Conclusions The licensee review and audit, and design change activities were consistent with the framework of their license requirement .0 Operator Requalification Program Insoection Scoce (69003)
The inspector investigated whether the licensed oport. ors had current licenses and physical examinations, and had completed the requirements of the requalification program as approved by the NRC, Observations and Findinas The requalification program was submitted by the licensee on January 7,1997, and was approved by the NRC on February 19,1997. It required that each licensed operator be administered an annual operating test by designated individuals. Section 2.4 specifically delegated the Reactor Manager, Operations Engineer, Training Coordinator, and Shift Supervisors to administer the test The inspector determined that the tests administered throughout 1997 to the four Shif t Supervisors, Training Coordinator, Operations Engineer, and one senior operator were conducted either entirely or partially by senior reactor operators that either reported to them or wer. their coworkers. This is a violation of the requalification program requirements (50-186/98201-01).
The licensee acknowledged that the evaluations should have been administered by only those designated and will readminister tests to the affected operators within 30 days following this inspection. The cause appeared to have been a misinterpretation of the requirements by the licensee's staff, since every licensed senior reactor operator staff member had the ability to perform shift supervisor duties and had the tec'nnical competence to have evaluated performanc _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ ______ ___ _ _ - _ _ - _ _ _ _ _ _ _
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The inspector verified the licensee grading of bieri '3-1 written examinations and found that they were scored accuratel A sampling of licensed operators on-shift found that they had current licenses end inedical examination (Closed) Follow Un item 96001-01: The inspector verified that the licensee implemented corrective actions in the revised NRC approved requalification program which required alllicensed operators to be administered a blennial written examination that they were not involved in developing, Conclusion The requalificetion program was implemented in accordance with the requalification plan with one exception as describe .0 Procedures Insoection Scoce(42745)
The inspector investigated whether the licensee's administrative controls were consistent with requirements; procedures met TS and administrative requirements; procedures were used as required; and procedures in use were current, reviewed, and approved as required, Qhsa;vations and Findinas Procedures Review Subcommittee minutes and recent procedure revisions were reviewed. The inspector made observations of procedure use in the control room. No concerns were identified, Conclusions Procedures were reviewed, approved, and used as require .0 Fuel Movement insoection Scoce (60745)
The inspector investigated whether procedures were adequate, TS were met, and problems were resolved, Observation: and Findinos A sampling of fuel rr.ovements were reviewed and no concerns were identifie Conclusion The fuel movements reviewed met all requirement _ - _ - - - _ - - l
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4 Surveillance Insoection Scone (61745)
The inspector investigated whether procedures met the requirements; surveillances were performed as required; and records and logs of safety parameters were consistent with surveillance result Observations and Findinos The inspector noted that the Rod C monthly drop time had increased since last November from about 520 to 620 milliseconds although it was still within the specification of 700 millisecond Tho licensee was aware of the change which occurred after the rod assembly -
was refurbished in November. They plan to remove the rod and attempt to identify and correct the cause of the change by the end of January 199 The licensee notified the NRC by telephone on January 29,1998 that the control rod C problem had bc. 7 corrected by replacing the offset mechanism and that the rod drop time had returned to norma A failure to meet TS requiremants for one channel of low primary flow reactor trip protection was discovered by the licensee during routine annual surveillance on June 16,1997. The channel was set 25 gallons per minute (gpm) below the Limiting Safety System Setting of 1600 gpm. The channel was reset 6nd retested with acceptable results each following week until a replacement was installed on July 14,199 The licensee reported this event to the NRC as require k This nonrepetitive licensee identified and corrected violation is being treated as a Non-Cited Violation, consistent with Section Vll.B.1. of the NRC Enforcement Fohc Conclusion The licensee's surveillance program acceptably met NRC requirements and Enforcement Policy standard .0 Experiments a, insoection Scoce (69005)
The inspector investigated whether experiments were handled in accordance with the licensee's requirements arid limit !
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5 Observations and Findinas The inspector observed licensee staff loading and documenting sample movement within the center flux trap holder. The operator was then observed while making entries in the sample log book. No concerns were identified, c, Conclusion The licensee had explicit instructions and procedures for handling experiments which the staff followe .0 Emergency Preparedness
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The inspector investigated whether emergency plan changes were in accordance with regulations and administrative controls; implementation procedures were consistent with the program; key responce personnel were able to implement the plan; offsite support was capable of assistance; and drills, exercises and training were conducte b, Observations and Findinas The licensee modified their implementing procedures to curect some minor problems identified in the annual drill. Of tsite organizations were involved extensively with the drill. Documented self evaluation was thorough and objective. Annual training included procedure corrections, Conclusion The licensee's emergency plan was effectively implemented as require .0 Event Follow Up Insoection Scoce (92700)
The inspector investigated the deteils of the event and its in pact on safety, possible causes, and licensee actions taken or planne Observations and Findinas The licensee reported to the NRC by telephone, and in writing within 30 days (nn January 8,1998) as required that they experienced an unexplained reactor high power trip on December 9,1997. The event occurred about 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> after retuming the reactor to full power following a rofueling and maintenance pened on December 8,199 .
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The re9ctor scrammed when Wide Range Monitor channel 4 reached 118 percent. Pov.or channel 6, close to channel 4 yet further from the core, indicated a rod run in set point had been reached and had a slightly lower peak on its recorder trace than channel 4. Power channel 5, located some distance from channcis 4 and 6 and reading the lowest before the event, did not indicate any power increase during the event, because of a sticking pen in the channel 5 chart recorder. The protective functions of channel 5 were oportional, but were not reached during the event. The event was also detected by the channels 2 and 3 (intermediate range).
Nuclear channel 5 recorder pen had not indicated a sudden power increase like the othei channels had during the trip event. The licensee suspected the pen had become stuck t'ut could not reproduce the problem during test!ng. The inspector reviewed the pen trace from the previous day's reactor startup and discovered the pen had been stuck for a period of time. This information supported the licensee's theory that the chanN 5 pen had been stuck during the even The Technical Specification limiting safety system setting for power was 125 percent. The licensee was operating at slightly less than 10 megawatts which was the license limit. The three nuclear channels that provide high power trips were all reading at o4 above 100 percent indicated power although the hourly primary cooling loop calorimetric readings and a pool heat balance calculation verified that power was less than the licensee limit 15 minutes before the even The licensee stated that the three channels were allowed to remain above 100 percent during the typical week-long run because es fission product poisons built up, fuel depleted, and rods withdrew, the shadowing effect on the nuclear instruments was continuously increasing and would otherwise have required constant adjustment to the instruments. At the time of the event channels 3 and 4 indicated 104 percent while channel 5 was at 100 percent. Operators confirmed that they were instructed to maintain the three affected channels within a range of about 100 to 105 percent at full power. Daily heat balance calculations were used to confirm the hourly calorimetric readings. The inspector verified daily heat balance calculations using logged parameters and
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verified that trip settings on all three channels were set below the 125 percent limi A review of the licensee's Hazard Summary Report (HSR) and applicable addendums that discussed reactivity insertions and limits confirmed that the licensee's assumptions and estimates of the amount of reactivity added were consistent with those predicted for similar scenario Discussions with the operators on duty during the event as well as records and log reviews led the inspector to conclude that operations before and during the occurrence appeared to be within license limits and administrative guideline Scram settings prevented the reactor from exceeding safety limits and limiting safety system setting _ -___ ______ __ -___ __ -
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The licensee investigated the possibility that fuel movement caused the even The licensee surveyed the operating crews involved in the December 8,1997, refueling and concluded that the core had been reloaded as planned with all fuel elements seated in their appropriate positions. The fuel elements were also subject to downward forces due to primary cooling flow which had exceeded the amount necessary to seat fuelin the core. Ucensee calculations indicated that, with the dimensional tolerances for fuel movement, it would have required all eight fuel elements to have moved to cause the reactivity event, it was unlikely that fuel movement in the core at power had contributed to this even The central flux trap and the samoles it contained were also considered by the licensee as a possible source of positive reactivity that may have caused the high power transient. Operators that installed the sample holder confirmed to the licensee that the device was latched in place as require A review of the contents cnd a physicalinspection of the samples in the trap during the event revealed nothing unusual. Vacuum testing and heat testing for leaking samples revealed nothing with any source of reactivity that was plausibl Af ter consulting with the Reactor Action Subcommittee, on December 10, 1997, the licensee started the reactor without the samples in the flux trap and compared the results during a second startup with the samples in place and accounted for the predicable reactivity difference The inspector observed the operators loading the flux trap holder with samples, verifying that it was full, and returnino the holder to its latched position. With the epparent rigorous procedure r- <ance, second verification and the positive locking system for the ' 4,it was unlikely that it could have contributed to this even The inspector reviewed records of maintenance activities preceding the event to identify any potential precursors Recent maintenance on the Uninterruptible Power Supply was reviewed. All nuclear instrumentation channels were either directly or indirectly powered from that source. Nothing was apparent that may have had any affect on the even The licensee hypothesized that a release of gas from the graphite reflector material could have caused a positive reactivity addition and may also separately have caused an increased neutron flux in the area of the channel 4 and 6 nuclear detectors. Both of these effects would have caused a higher power indication on those channels as a result. The licensee observed bubbles coming from the graphite in the vicinity of the channel 4 nuclear detector during startups after the event. The licensee's HSR predicted that a voidir g of the rod gap would cause positive reactivity as would voiding in the fiux tra They supported this theory with the results from modeling data. The graphite segments were Helium filled in aluminum cladding. The total voiding of the rod gaps would not result in a prompt critical condition however according to the HSR Section 13. . - _ _ _ _ _ - _ - _ _ _ - _ _ _ _ _ _ _ _ _ __
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This theory appears plausible and was a possible cause of the event although there was no means of verifying i The licensee also hypothesized that the boral control blades may have contributed to the event by releasing helium trapped within them. They plan to inspect the blades during outages in January and February 1998. They indicated to the inspector that this schedule may be extended except that C rod will be removed for inspection as discussed in Section Conclusion Although the licensee had not been able to definitively state what caused the positive reactivity resulting in the high power scram, their efforts to identify and characterize the magnitude of positive reactivity and plausible sources were comprehensive. No safety limits or limiting safety system settings appeared to have been exceeded. No similar event had ever occurred before. Although a possible recurrence cannot be discounted, the potential magnitude of another transient, although uncertain, would likely be less than a prompt critical condition as described in the HSR for rod gap voiding and based upon limits associated with reactivity worths permitted in the core regio .0 Miscellaneous Insoection Scone (86740)
The inspector investigated contact dose readings on a shipping container to determine whether the container was within dose limits for transportation as an empty package, exempt quantity, Observations and Findinas (Closed) Follow-Uo item 97201-03: The licensee had shipped a depleted uranium shielded container to a licensee in New York state in 1996 as an empty package, exempt quantity. The recipient measured contact readings on the package and had concluded that it exceeded the limit of 0.5 mrem /hr. The inspector verified the container was the same one that had been shipped to New York state in 1996 and measured the container using a Victoreen 471 calibrated in September 1997. All contact readings were within the mrem /hr limit established by the Department of Transportation for empty packaging, exempt quantitie Concl4:i1QD No further action require l
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11.0 Exit Meeting Summary The inspector presented the inspection results to members of the licensee management at an exit meeting on January 15,4998. The licensee acknowledged the findings presented. The inspectors asked the licensee whether any material examined during the inspection should be considered proprietary. No proprietary information was identified, s
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Partial List of Persons Contacted Edward Deutsch' MURR Director Charles McKibben' MURR Assoc. Director Walt Meyer' MURR Reactor Manager Tony Schuone' MURR Operations En * Denotes those attendin0 the exit meeting on January 15,1998 Inspection Procedures Used IP 39745 Organization and Operations and Maintenance IP 40745 Review and Audit and Design Change IP 69003 Reactor Operator Requalification IP 42745 Procedures IP 60745 Fuel Movement IP 61745 Surveillance IP 69005 Experiments IP 82745 Emergency Preparedness IP 92700 Follow-Up of Nor.coutine Events items Opened and Closed Ooened 50 186/98201-01 VIO Failure to conduct anaual operating tests by authorized individual Closed 50-186/96001 01 IFl Requalificati on written examinatio /97201-03 IFl Proper labeling for empty packagin List of Documents Reviewed Hazard Summary Report Operating Procedures Reacter Operating License Training Records Technical Specifications Maintenance Records Administrative Procedures Various Reports Surveillance Procedures List of Acronyms Used CFR Code of Federal Regulations HSR Hazard Summary Report mrom millirem MURR Research Reactor Facility NRC Nuclear Regulatory Commiss')n POR Public Document Room TS Technical Specifications
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